1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

CleanCache Merged Into The Linux Kernel

Linux Kernel

Published on 26 May 2011 03:18 PM EDT
Written by Michael Larabel in Linux Kernel
13 Comments

While the first Phoronix benchmarks of EXT4, Btrfs, and XFS on the Linux 2.6.39 kernel were just published this morning, an interesting change was just made for the next Linux kernel that will affect many of the file-systems living within the kernel. For what will be the Linux 2.6.40 kernel, or rather the Linux 3.0 kernel is the finally-merged support for CleanCache.

The CleanCache patch-set began as part of the Transcedent Memory patch-set more than one year ago (and discussed long before that), but with Linux 2.6.40/3.0 it's finally being merged. In fact, the patches just hit the Linus Torvalds Git tree in the past couple of hours. The documentation describes this CleanCache feature as:
This patchset introduces cleancache, an optional new feature exposed by the VFS layer that potentially dramatically increases page cache effectiveness for many workloads in many environments at a negligible cost. It does this by providing an interface to transcendent memory, which is memory/storage that is not otherwise visible to and/or directly addressable by the kernel.

Instead of being discarded, hooks in the reclaim code "put" clean pages to cleancache. Filesystems that "opt-in" may "get" pages from cleancache that were previously put, but pages in cleancache are "ephemeral", meaning they may disappear at any time. And the size of cleancache is entirely dynamic and unknowable to the kernel.

There's also this documentation file in the kernel for those wishing to learn more of the technical and implementation details. For the rest, CleanCache simply is designed to offer faster file-system performance. In particular, when there is high memory pressure there should be sizable improvements and for most workloads. "Basically cleancache replaces I/O with memory-copy-CPU-overhead; on older single-core systems with slow memory-copy speeds, cleancache has little value, but in newer multicore machines, especially consolidated/virtualized machines, it has great value."

As part of the push into the linux-2.6.git tree today, there is CleanCache support for the EXT3, EXT4, Btrfs, and OCFS2 file-systems. Other file-systems will also likely be supported in the future. Within the Xen area is also a CleanCache shim to the Transcendent Memory.

It should come as no surprise, but Linux CleanCache benchmarks will be published on Phoronix quite soon.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  2. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  3. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
  4. AMD Radeon R9 285 Tonga Performance On Linux
Latest Linux Articles
  1. Ubuntu 14.10 XMir System Compositor Benchmarks
  2. Btrfs RAID HDD Testing On Ubuntu Linux 14.10
  3. Ubuntu 14.10 Linux 32-bit vs. 64-bit Performance
  4. AMD Moves Forward With Unified Linux Driver Strategy, New Kernel Driver
Latest Linux News
  1. Debian 8.0 Jessie Has Many Multimedia Improvements
  2. What Linux Benchmarks Would You Like To See Next?
  3. Open-Source, Linux Support For Corsair Link Devices Slowly Materializing
  4. Cairo-Dock 3.4 Shows A Lot Of Progress, Works Toward EGL/Wayland Support
  5. Mesa 10.4 Tentatively Planned For Early December
  6. SteamOS Update 145 Brings Compositor, Update Fixes
  7. GStreamer 2014 Conference Videos Posted: Wayland, HTML5, 3D
  8. Nouveau Now Supports DRI3 Without GLAMOR
  9. Features Of The Linux 3.18 Kernel
  10. Debian Now Defaults To Xfce On Non-x86 Desktops
Latest Forum Discussions
  1. Updated and Optimized Ubuntu Free Graphics Drivers
  2. Linux hacker compares Solaris kernel code:
  3. HOPE: The Ease Of Python With The Speed Of C++
  4. Users/Developers Threatening Fork Of Debian GNU/Linux
  5. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  6. AMD Releases UVD Video Decode Support For R600 GPUs
  7. Proof that strlcpy is un-needed
  8. xbox one tv tuner